PEL 0058: Block 2113A

 

 

 

Regional Setting & Petroleum Geology

Nabirm’s petroleum exploration license (PEL 0058), Block 2113A MAP, offshore Erongo Province, Namibia covers 5,750 km2, with 3,600 km2 located offshore and 2,150 km2 located onshore. PEL 0058 is located inboard of the Tullow/Pancontinental‟s PEL 0037 Block and adjacent to the Galp/ExxonMobil Blocks 2212A & B, PEL’s 82 & 83 respectively.

In 2014, Pancontinental Oil & Gas, in partnership with Tullow Oil Plc  mapped an “Oil Mature Fairway” PEL 0037 and the HRT Wingat-1 well area. Critically, using existing seismic data, good reservoir rocks were interpreted in channels and turbidites within and close to the ‘Oil Mature Fairway’ in PEL 0037 which is adjacent to PEL 0058. DeGolyer and MacNaughton(“D&M”) prepared this assessment of licence area PEL 0037 offshore Namibia in accordance with the Petroleum Resources Management System (PRMS) approved by the Society of Petroleum Engineers, the World Petroleum Council, the American Association of Petroleum Geologists, and the Society of Petroleum Evaluation Engineers.

D&M’s resource estimates recognize large stratigraphic leads in potential clastic turbidite targets. These targets appear to be in the oil window. These potential accumulations are categorized as “leads” based on the available seismic and geologic data. The potential accumulations are not yet classified as “prospects” that are available for drilling. D&M’s Mean Estimate for the total 11 Leads is 8.7 Billion Barrels of Gross Prospective (recoverable) Oil Resources.

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Oil Mature Fairway

Prospectivity

Nabirm concluded a 2D seismic survey which included the acquisition of gravity and magnetics data.The 2D acquisition project scope consisted of a FIRM 684 full fold km of 2D marine seismic acquisition including renewed gravity and magnetics. The survey consisted of 24 lines including 5 strike lines (oriented parallel to the Namibia coast) and 19 dip lines (oriented perpendicular to the Namibia coast).

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Location of PEL 0058 Offshore Erongo Province Namibia.

Leads

An interpretative study was completed with the integration of regional data identifying key depositional features (reflection types, continuity, terminations, down-lap, top lap, on-lap), structural features (highs, lows, faults and fault styles including normal, reverse, strike-slip)and anomalous reflection packages. Six leads with total Pmean un-risked recoverable resources of over 520 MMBO were mapped. Stratigraphic lead 5  is the largest and of principal interest, with a Pmean of around 230 MMBO. Lead 6 is slightly smaller and exceeds 200 MMBO.

Migration pathways

A 3D Basin Model was generated by DSP Geosciences post 2D seismic. The objective of the Basin Model was to provide an overview of Namibian margin hydrocarbon maturation with a focus on Nabirm PEL 58, Block 2113A.  The cross- section shows the sea floor, Cretaceous-Tertiary Boundary, Mid-Cretaceous proxy and Basement surfaces. The location of the Murombe and Wingat wells are shown, and the interval where oil was recovered from the Wingat well. Top early oil generation, top peak oil generation and the gas window are shown. A migration vector from the oil generation window is shown moving up-dip and landward toward Block 2113A.

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3D Basin Model

The maturity and hydrocarbon migration model above shows clear up-dip drainage for hydrocarbons. Recent studies by AW Upstream Oil & Gas confirm this trend. Some leads identified in neighbouring block show on-laps and pinch-outs of predicted Lower Cretaceous sands against basement reinforced by amplitude anomalies with a “soft kick”. Likely migration pathways are intra-source sand stringers, as they occur in the Kudu shale at Wingat-1, other Lower Cretaceous sands covered with a tight regional seal, and unconformity surfaces such as the top basement and Mid Albian unconformity. Reactivated syn-rift fault that extend up into the Cretaceous post-rift sequence can relay drainage from stratigraphically deeper to shallower levels.

Lower Cretaceous sands are likely only preserved in local depressions and hanging wall traps in Block 2113A. Therefore the top basement unconformity is regarded as a main conduit for hydrocarbon migration to charge the leads in Block 2113A. This surface is most likely connected to down-dip carrier beds such as intra-source sand veneers. The HRT (2011) study on hydrocarbon seepage shows seepage directly next to the north-western and south-western corner of the Nabirm acreage.With the DSP Geoscience study two migration vectors at basement level were calculated that indicate possible charge of two areas in the Nabirm acreage. The southern vector could charge leads shown above. The conclusions of the 3D Basin Modeling indicate that there is a proven, working Aptian- Barremian petroleum system in both syn-rift and early transgressive rift-to-drift flooding event in offshore Namibia. Maturation modeling within the 3D Basin Model AOI indicates that a Mid-Cretaceous proxy surface has maturation values indicating early maturity in the western AOI.  Maturity at the Basement horizon level indicates oil and gas generation is possible in the western portions of the Nabirm Block 2113A 3D Basin Model AOI.